Brucellosis among bacteriology and research laboratory workers from Argentina.

WALLACH J; DELPINO MV; FERRERO MC; BALDI PC; FOSSATI CA

Inglaterra

Congreso; Brucellosis 2008 International Research Conference (2008); 2008

Laboratories with BSL2 and BSL3 facilities, required for clinical bacteriology studies and massive culture of Brucella, respectively, are very scarce in Argentina. Workers from hospital microbiology services usually process blood cultures without special personal protection or precautions for airborne pathogens. Since brucellosis is endemic in our country, some of these cultures may later yield Brucella spp. In addition, researchers working wtih live brucellae may be also exposed to these bacteria. In our practice we have noted an increase of brucellosis cases related to laboratory infections in recent years. From 2002 to 2006, 8 of such patients consulted to our service, including 4 researchers, 3 clinical microbiology laboratory workers and 1 technichian involved in fetal bovine serum (FBS) production. The population included 5 males and 3 females, from 29 to 54 years (mean 37,6 years). Epidemiological investigation demonstrated 4 kinds of exposure: accidental (noticed) exposure to Brucella cultures (2 cases), processing of human blood cultures that later yielded Brucella spp. (3 cases), occasional work in laboratories in which Brucella was being handled (2 cases), and processing of bovine blood (1 case). The later 3 cases were classified as suspected exposures. The two accidental exposures were due to the explosion of an electroporation cell containing a pure culture of Brucella abortus. The electroporator was not located inside a biological safety cabinet. The three cases related to blood culture processing were caused by Brucella suis (later identified in the samples). Brucella could not be isolated in the 3 patients with suspected exposure. The infection was assumed to have been acquired by the inhalatory route, except in the patient involved in FBS production, who reported mouth pippeting. None of the patients had a documented previous brucellosis. Only 2 patients reported other potential sources of Brucella infection. In patients with known exposure date (accidental exposures and processing of blood cultures) the time elapsed from exposure to clinical presentation ranged from 6 to 16 weeks (mean 8.8 weeks). Common clinical findings were fever (8 cases), asthenia and sweats (5 cases each), myalgias, headache and digestive complaints (4 cases each), and arthralgias, insomnia, irritability and hepatitis (3 cases each). All patients were positive by the Rose Bengal test and exhibited significant titers in confirmatory serological tests, including standard tube agglutination (100 to 6400), 2-mercaptoethanol (25 to 1600) and complement fixation (10 to 640). Antimicrobial therapy included doxycycine + rifampin (4 cases), doxycycline + streptomycin (2), doxycycline + gentamicin (1) and doxycycline alone (1). Six patients experienced clinical remission after therapy, one had persistent hepatitis, and the patient who processed FBS had a severe clinical relapse with miopericarditis. The later case remitted after a second course of doxycycline and rifampin. In countries endemic for Brucella and with scarce biosafety facilities, personnel involved in bacteriological diagnosis may often become exposed and infected by this bacterium. Accidental and unnoticed exposures may also occur in research laboratories working with Brucella, stressing the importance of BSL3 laboratories availability for this purpose.